Miriam Lantsbury hadn't even stepped on the canal towpath when she was hit. She used to like walking to work along the narrow thoroughfare beside the Regent's canal as it wiggles its way from Hackney in east London to the City.

But that was before her collision with a cyclist. "I was just coming down the steps and my hand went round the corner when it happened," she says.

The impact of the bike's handlebars broke the 48-year-old's hand. "It's such a lovely place to walk to work, especially on day like today, but the accident has really put me off – it's too busy and scary," she says.

Lantsbury and other pedestrians have become the victims of the success of campaigns to encourage more people to take up cycling. They say they are being forced off the towpath by the daily charge of the Lycra brigade.

On the spot where Lantsbury was hurt, the path is so narrow you can almost touch the water with one hand and the side of the steps with the other.

"You can't walk more than one abreast. It's real shame, that we can't share it, not just for me but for families taking children to school."

In the last 12 months there have been 33 complaints and reports of accidents on the Regent's canal alone. One complained of "towpath rage"; another said it was becoming like a "racetrack". Comments like these have forced British Waterways, which runs the 2,000-mile canal network, to intervene.

It has appointed its first towpath warden to calm the increasingly fraught relations between walkers and bikers.

On his first day on the canal, Joseph Young is keen to flag down speeding bikes. "A minority of cyclists are using the towpath purely as a commuter route to get as fast and they can to work. They are the ones I want to target."

Young will be cycling himself to patrol a 100-mile stretch of the canal, armed only with a bell and a florescent bib with the words "slow down" printed on it.

Before taking to his bike, Young and a team of volunteers surveyed cyclists and raised awareness about a code of conduct aimed at encouraging responsible riding.

They counted 270 cyclists in just over an hour, and in the same time fewer than 20 pedestrians.

The team has been handing out bells and "Two Tings" stickers urging cyclists to "ting your bell twice - pass slowly, be nice!"

Young's first task once on the bike is to investigate a loose speed barrier near the City basin. He cycles impeccably slowly. Everyone gets a polite double ring from Young's bell, the constant soundtrack to Young's role. "I'm sure I'll get sick of it pretty quickly," he confesses.

Young is convinced that despite the dwindling number of pedestrians there is room on the path for those on foot as well as on bikes. "We want as many people as possible to use the canal. As long as people are considerate I don't see why it can't work."

Others are not so sure. Howard Piper, the trustee of a local charity that organises barge trips, questions why bike riding has been so heavily promoted on the canal.

"The London mayor, British Waterways, Transport for London, everybody is encouraging cycling. Therefore it is has grown exponentially. But it means that gradually there has been an erosion of people walking down here.

"You are risking injury if you do and worst of all the quality of the experience is being eroded by cyclists."

He argues that bikes should be banned from the towpath if accidents continue. "If that is what it takes to make the paths safe again, then it should be considered as a last resort."

Jake, one of the cyclists issued with a sticker, hopes this won't happen. "It's a great way to get to work, it would be terrible if they took this away," he says.

"I had a crash with another cyclist once – we hit each head-on. Since then I've slowed down. Now I relax and think it's not a race, it's about enjoying the cycle path."

Lantsbury wishes more cyclist would do the same. "I would love to walk on the paths in the morning again, but only when everyone's slowed down."